So your strut is in the hub and the hub is located on the steering arms and ARB but the wheel is sitting on its outside edge? There won't be much difference I don't think between all the Sierra hubs on that measurement. I don't think changing front hubs on a Cossie would alter the camber.

Can you adjust other parts of your suspension to compensate? Have you got a photo? Have you looked at pictures online of Cossie hubs to compare them to what you are using?

Charlie